Strategy: This one is simple. Hit Big Smaug (from Along the Shore 2.5) as many times as you possibly can. No mystery here. This camp drops Vault Chests which contain pearls and various levels of valto runes when attacked by Bard with the correct gear.
When hitting the ATS Smaug, better chests will drop for Bard equipped with his Black Arrow, BAI, BAII, or BAIII. Additonally, Bard can be equipped with the rest of your standard defense gear to help decrease your troop loss on Smaug.